Fabry-Pérot based structures can be used to detect a variety of optics and measurements, as well as for determining strain, temperature, acoustic waves, and various other properties and physical parameters. The present technology provides a self-referencing composite Fabry-Pérot cavity sensor. According to various aspects of the present technology, the composite Fabry-Pérot cavity sensor is able to detect a change in thickness and refractive index of a dielectric material upon exposure to a sample, allowing for accurate measurement detections regardless of the dielectric material thickness, refractive index, light incident angle, and wavelength.
In various aspects, the present technology provides an optical sensor device comprising a substrate. A first cavity portion is disposed within the substrate having a first depth, and a second cavity portion is disposed within the substrate and having a second depth. The first cavity portion is juxtaposed to the second cavity portion and the first depth is offset by a predetermined distance from the second depth. A dielectric material is disposed within the first and second cavities.
In another aspect, the present technology provides a self-referencing composite Fabry-Pérot cavity sensor. The sensor includes a substrate defining composite cavity including a first portion juxtaposed to a second portion, wherein the first and second portions are provided having a predetermined depth offset. A polymer is disposed within the cavity. An interference spectrum resulting from a light source of a known wavelength reflecting through the sensor produces a first refractive index from the first portion offset by a second refractive index from the second portion.
In still another aspect, the present technology provides a self-referencing composite Fabry-Pérot cavity sensor comprising a substrate defining a first cavity juxtaposed to a second cavity, wherein the first cavity and second cavity have a predetermined depth offset. A dielectric material is disposed within the first and second cavities. The dielectric material provides a first reflection surface defined by a plane surface level with a bottom of the first cavity, a second reflection surface defined by a plane surface level with a bottom of the second cavity, and a third reflection surface defined by a plane surface flush with both a top of the substrate and a top of the dielectric material. An interference spectrum resulting from light reflecting through the sensor produces a first reflectivity from the first reflection surface, a second reflectivity from the second reflection surface, and a third reflectivity from the third reflection surface.
The present technology also provides a method of detecting a physical parameter using a self-referencing composite Fabry-Pérot cavity sensor. The method comprises providing a substrate including a first polymer filled cavity juxtaposed to a second polymer filled cavity. The first and second polymer filled cavities have respective depths offset by a predetermined distance. The method includes passing a vapor analyte sample over the substrate for detection while introducing a light source into the first and second cavities. A first refractive index is measured from the first cavity and a second refractive index is measured from the second cavity. The method includes analyzing a difference between the first refractive index and the second refractive index and determining the physical parameter.
Still further, the present technology also provides a method of making a self-referencing Fabry-Pérot sensor. The method comprises forming a first cavity in a substrate having a uniform first depth, and forming a second cavity in the substrate juxtaposed to the first cavity and having a uniform second depth. The second depth is offset from the first depth by a predetermined distance. A dielectric material is provided disposed within the first and second cavities.
Further areas of applicability will become apparent from the drawings and description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.